Рабочие листы
к вашим урокам
Скачать
1 слайд
BONDS
IN
LIQUIDS & SOLIDS
2 слайд
INDEX
INTRODUCTION
METALLIC BONDS
IONIC SOLIDS
NETWORK SOLIDS
DIPOLE–DIPOLE FORCES
VAN DER WAALS FORCES
HYDROGEN BONDS
3 слайд
INTRODUCTION
In the solid or liquid phase molecules are very close to each other.
We have already studied intramolecular bonds in molecules now, we will examine intermolecular forces of attraction in liquids and solids.
4 слайд
METALLIC BONDS
Metals are solid at room temperature except for mercury.
The attraction forces between metal atoms are strong.
The valence electrons of metal atoms can easily move from the free orbitals of one atom to another and form an “electron sea”.
5 слайд
Attraction force between the negatively charged “sea of electrons” and the positively charged nuclei holds atoms together.
This is called the metallic bond.
In a group, metallic bond strength generally decreases from up to down.
In a period, strength generally increases from left to right.
6 слайд
7 слайд
Metals are good conductors of heat and electricity
Metals can be drawn into wires and hammered into shape easily.
8 слайд
9 слайд
Metallic bond is better maan!
10 слайд
11 слайд
The metallic bonding in Al is the strongest, and the weakest in Na.
12 слайд
IONIC SOLIDS
When metal and nonmetal atoms come together, they form ionic bonds
Electrostatic attraction occurs between
the positive and negative charges holding the ions together.
Metal ions are surrounded by nonmetal ions and nonmetal ions surrounded by metal ions.
13 слайд
.
Ionic solids do not have a molecular structure.
The melting and boiling points of ionic solids are very high
Aqueous solution and molten state conduct electricity.
Don’t conduct electricity
Brittle, not ductile and can not be drawn into wires or hammered into plates.
Very stable
14 слайд
NETWORK SOLIDS
In some covalent substances, known as network solids, atoms are bonded together in a way that forms a network structure.
15 слайд
Diamond
Each carbon atom is covalently bonded to four other carbon atoms forming a tetrahedral shape.
The hardest natural substance.
The bonds are formed by sp3-sp3 hybrid overlap.
16 слайд
Silicon carbide SiC is another network solid.
Silicon carbide is used as an abrasive because of its hard structure.
17 слайд
Diamond and silicon carbide are nonconductors of electricity and have very high melting points.
18 слайд
Graphite
Each carbon atom is bonded to three other carbon atoms with an angle of 120° between the bonds.
The bonding involves sp2 – sp2 hybrid overlap.
Because of weak bonding between the layers, the layers can slide over each other.
Conduct electricity.
19 слайд
20 слайд
DIPOLE–DIPOLE FORCES
The atrractions of the positive and negative poles of the molecules are called dipole–dipole forces.
H2O ,HCl , NH3, H2S , PH3 , SO2 are samples.
Dipole - dipole force is much weaker than the covalent bond within the molecule.
21 слайд
d+ d-
d+ d-
d+ d-
d+ d-
d+ d-
d+ d-
d+ d-
d+ d-
Dipole- Dipole Interactions
22 слайд
23 слайд
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
Dipole- Dipole Interactions
24 слайд
VAN DER WAALS FORCES
The intermolecular forces between nonpolar molecules in the liquid and solid state.
By movement of electrons, nonpolar molecules becomes temporarily polar.
The momentarily polar molecule makes polar its neighboring molecule.
Thus a weak attraction occurs between the molecules.
25 слайд
Increasing number of atoms in a molecule increases the van der Waals attractive force.
Van der Waals forces are stronger between molecules with high molecular masses.
For small molecules, the van der Waals force is weaker than dipole - dipole forces and hydrogen bonding.
26 слайд
27 слайд
28 слайд
Formation of van der Waals forces. Molecules approaching each other gain a momentarily polar character.
29 слайд
Gecko, a kind of lizard, is able to move freely on very smooth ceilings, on glass as well as on waxed surfaces as if it challenges to gravity , attract the attention of scientists.
30 слайд
HYDROGEN BONDS
An extra strong dipole-dipole attraction that occurs between molecules in which hydrogen is covalently bonded to the electronegative elements N, O and F.
31 слайд
Hydrogen bonds between water molecules are stronger than dipole-dipole and van der Waals forces.
32 слайд
HF
H2O
NH3
Hydrogen bonds HF>H2O>NH3
33 слайд
Because of hydrogen
bonding the boiling points of HF,H2O
and NH3 are greater than expected.
34 слайд
Ionic bond
here
Ionic bond
covalent bond
metallic bond
hydrogen bond
James bond
He! He ! He! absent
35 слайд
36 слайд
Each of snowflakes is different from each other. As there are no two same people from the creation of human being, there are no snow crystals being completely same of the other one.
Рабочие листы
к вашим урокам
Скачать
6 626 961 материал в базе
Настоящий материал опубликован пользователем Джумаев Бахтыяр Нарзыевич. Инфоурок является информационным посредником и предоставляет пользователям возможность размещать на сайте методические материалы. Всю ответственность за опубликованные материалы, содержащиеся в них сведения, а также за соблюдение авторских прав несут пользователи, загрузившие материал на сайт
Если Вы считаете, что материал нарушает авторские права либо по каким-то другим причинам должен быть удален с сайта, Вы можете оставить жалобу на материал.
Удалить материалВаша скидка на курсы
40%Курс профессиональной переподготовки
500/1000 ч.
Курс повышения квалификации
72 ч. — 180 ч.
Курс профессиональной переподготовки
300 ч. — 1200 ч.
Мини-курс
4 ч.
Оставьте свой комментарий
Авторизуйтесь, чтобы задавать вопросы.